Many inflatable mattresses and cushions are used to provide added comfort and support to individuals who are in a sitting or supine position for a prolonged period of time. Some of these mattresses and cushions are adapted to be placed upon a hospital bed or upon wheelchair seats to reduce the likelihood of developing bedsores.
Inflatable air mattresses adapted to prevent bedsores are disclosed by Chamberland in U.S. Pat. No. 4,896,389 and Afeyan in U.S. Pat. No. 4,914,771. Each mattress is formed of two sheets of plastic material comprising of a plurality of elongated pillows adjacent to and parallel to each other which are formed by folding the upper sheet and a base portion having two air distribution channels or plenums disposed along the full length of both sides of the mattress. The ends of the pillows communicate with the plenums. A pumping means provides air flow to the plenums via a tubular hose to inflate all pillows of the mattress to a constant uniform pressure.
It is known in the art to use inflatable mattresses or sheets having separate zones of pillows which can be independently pressurized to reduce the likelihood of developing bedsores. Each zone is alternately inflated and depressurized to vary the load upon the portion of the person's body in contact with the mattress. At present, such mattresses generally employ a number of discrete tubular hoses and fittings connected to each of the pillows to be alternately inflated and deflated. This construction, however, is cumbersome to use and difficult and time consuming to manufacture.
An inflatable sheet disclosed by Grant in U.S. Pat. No. 5,263,211 is another example of the use of independent zones of cells that are alternately inflated and deflated. The inflatable sheet comprises two sheets of plastic material sealed together to form two independent sets of interdigitated fluid cells. The arrangement of the cells and the dimensions thereof are limited because the cells act as both the cushioning means and the conduit to supply air to the cells.